1. Field of the Invention
The present invention relates to a changing system in a manual transmission, and more particularly to a changing system in a manual transmission in which a reverse idling gear is slid and meshed simultaneously with a first reverse gear secured to one of a main shaft and a counter shaft and with a second reverse gear mounted on a sleeve of a preselected synchronizing mechanism mounted on the other of the main shaft and the counter shaft, thereby establishing a reverse speed stage.
2. Description of the Related Art
Such a system is conventionally known, for example, from Japanese Patent Application Laid-open No. 2001-115142.
In the above-described conventionally known system, when the reverse idling gear is slid and meshed with the reverse gear mounted on the preselected synchronizing mechanism to establish the reverse speed stage a slight movement of the sleeve caused with the sliding and meshing of the reverse idling gear is inevitable. When the sleeve is moved slightly, the main shaft is difficult to rotate under the synchronizing action of the preselected synchronizing mechanism, and a thrust load upon meshing of the reverse idling gear with one of the first and second reverse gears, which is mounted on the main shaft, is increased, thereby bringing about an increase in reverse shafting load.
Accordingly, it is an object of the present invention to provide a changing system in a manual transmission, wherein the movement of the sleeve of the preselected synchronizing mechanism is inhibited when the reverse speed stage is to be established, thereby providing a reduction in reverse shifting load.
To achieve the above object, according to the present invention, there is provided a changing system in a manual transmission comprising a first reverse gear secured to one of a main shaft and a counter shaft, a second reverse gear mounted on a sleeve of a preselected synchronizing mechanism mounted on the other of the main shaft and the counter shaft, a reverse idling gear rotatably retained on a reverse shifting fork and capable of being slid in a direction parallel to the main shaft and the counter shaft so that said reverse idling gear can be meshed simultaneously with the first and second reverse gears, a plurality of shifting pieces arranged in parallel in a direction along an axis of a shift-selecting shaft capable of being moved in an axial direction in response to a selecting operation and turned about an axis in response to a shifting operation, the shifting pieces including a reverse shifting piece operatively connected to the reverse shifting fork and a preselected shifting piece operatively connected to a preselected shifting fork retaining said sleeve, a shifting arm fixed to the shift-selecting shaft and having a drive portion capable of being brought alternatively into engagement with one of the shifting pieces in response to the selecting operation, and an interlock plate which is mounted on the shift-selecting shaft for non-rotation about the axis of the shift-selecting shaft to cover a portion of the shifting arm, and which has a slit to which the drive portion faces, wherein the interlock plate is formed into a shape such that it inhibits the movement of the preselected shifting piece in the same direction as a direction of sliding of the reverse idling gear, when the shifting arm having the drive portion engaged with the reverse shifting piece is turned for shifting to establish a reverse speed stage.
With such arrangement, when the shifting arm is turned toward a reverse position to establish the reverse speed stage, the movement of the preselected shifting piece in the same direction as the direction of sliding of the reverse idling gear is inhibited by the interlock plate. Even if a force moving the sleeve is applied to the sleeve when the reverse idling gear is slid and meshed with the second reverse gear, the sleeve cannot be moved, because the movement of the preselected shifting piece operatively connected to the preselected shifting fork retaining the sleeve is inhibited. Therefore, such a phenomenon deteriorating the rotation of the main shaft under the synchronizing action of the preselected synchronizing mechanism during establishment of the reverse speed stage, cannot occur, and the thrust load upon the meshing of the reverse idling gear with one of the first and second reverse gears, which is mounted on the main shaft, cannot be increased, so that the reverse shifting load can be reduced.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.